It is a quote from the Bible. People use quotes from the bible all the time and they don't even know it. It means sharing something that is important to you with someone who won't appreciate it. I hope this makes sense.

wow - never! haha but it's cool. It must mean, something is being done which wont be appreciated - or it's a waste of time.

It's like "casting pearls before swine." I would probably say it to a friend if she was going to do something special for people who weren't going to appreciate her extra work and unpaid overtime on their behalf. The ingrates (ungrateful people)! Which reminds me of this cartoon I have of this huge tired pig sitting in a mud puddle. It says, "Never try to teach a pig to sing. It wastes your time and it annoys the pig." ^_^

The phrase comes from the Christian Bible. Jesus is preaching and says: Do not give what is holy to the dogs; nor cast your pearls before swine, lest they trample them under their feet, and turn and tear you in pieces." This means that scriptural truth or knowledge (pearls) should not be set before people people (swine, pigs) who do not or cannot appreciate their value. Giving an expensive wine to someone who always buys the cheapest possible alcohol might be considered casting pearls before swine.

Giving fine foods- caviar- rare cheese- to children, who want peanut-butter and jelly, is casting pearls to swine. Lending a new BMW or Porch to a teenage person that has never driven before- same thing. Giving new expensive white tennis shoes to a person that works in a sewer and often forgets their work boots- same.